Stop reading if you haven’t seen Season 4, Episode 7 of Game of Thrones, titled “Mockingbird”—unless you enjoy spoilers.

You know what they say about dramatic structure… if you introduce a Moon Door in the first act, it’ll have to go off in the third.

Chekhov’s Moon Door has been deployed, a bit earlier than we might have expected, and it’s Lysa Arryn’s turn to be cracked like an egg on the rocks below. Littlefinger has had a way lately of making a huge impact in his tiny amount of screen time, with a lifetime’s worth of lies now seeming to line up exactly the way he planned them. He’s the man who set off the entire plot of the show by plotting to kill Lysa’s husband Jon Arryn, and this season he’s reshuffled the deck of Westeros, twice, with a high-profile assassination. It’s only a pity he couldn’t toss snotty, awful Robin in after her.

Lysa’s death came out of nowhere, but it was fitting in an episode in which so many characters had their lives on the line. Tyrion was trapped in that dank jail cell the entire episode, watching his potential champions— Jaime due to injury, Bronn due to understandable self-interest— back out. Resigned to fight The Mountain himself and face certain death, Tyrion found a last-minute savior in the smooth, savvy Oberyn Martell, whose mission to avenge the death of his sister means he’s the only person in Westeros happy to fight Ser Gregor Clegane. Well, it helps that he’s hated Cersei even longer than that. After the lengthy story about meeting Tyrion as a baby, Oberyn’s “I will be your champion” was a huge, soaring moment. Which, if Game of Thrones sticks to its usual pattern, means crushing heartbreak next week. Strap on that armor tight, Oberyn.

The brief appearance in King’s Landing by The Mountain, pulling out entrails as easily as plucking a wishbone, led nicely into Arya and The Hound’s continuing solo adventures. The usual Hound brutality— stabbing a dying man through the heart, sewing shut his own neck wound— led to an unusually open moment, remembering the burned faced he earned at the hands of his brother, none other than The Mountain.

The speech draws yet another line under how close Arya and The Hound have become, and his continuing earning of sympathy— the look on his face when he says “I didn’t steal it, I was just playing with it” points to a man who’s never grown past that scarred seven-year-old. Arya and the Hound have been stalled in the story since witnessing the Red Wedding, but they ought to arrive soon at the Eyrie, which will be in chaos after Lysa’s death. And there’s also the bounty on the Hound’s head, which can’t only be on the brains of the half-wits who attacked him. Think that deep attachment we’ve formed with the Hound will come back to bite us?

Actually, I take that back about Arya being stalled in the story— thanks a chance encounter with Hot Pie, still obsessed with gravy and buttery crusts, Brienne and Podrick are on their way to the Eyrie as well. Game of Thrones is crawling with unlikely duos right now, but Brienne and Podrick are among the few allowed to toss in actual jokes, and the episode is better for the scant minutes we get with them. At the very least, it’s a relief to see two travelers visit a tavern without anyone getting stabbed in the chest.

Jon Snow, he of the big rousing speeches and the recent thrilling victory, is stuck at Castle Black dealing with a very familiar foe for the rest of us: bureaucracy. No old leader likes seeing the young upstart show him up. But freezing that tunnel sounds like a mighty good idea, and I’m guessing we’ll see Mance Rayder prove it before the season’s end.

Of all the characters in this episode who seem bound for death, I feel the least sorry for Daario, who gets a roll in the hay with Daenerys before being shipped off to fight for her in Yunkai. That was a sex scene a long time coming, and Dany’s lingering look at the naked Daario went at least a little toward making up the deficit of male flesh compared to all the bare-breasted women on the show. That’s not to say, though, that she actually seemed to be enjoying it. For Daenerys, still laser-focused on her anti-slavery crusade, bedding Daario was just one more power play, a symbolic removal of another chain (with, yes, an added bonus or two).

And finally, there’s Melisandre, balancing out Daario’s naked rear with plenty of her own nudity, and putting it to good work intimidating Selyse. It’s hard to top Stannis’s visit to the Iron Bank last week to make us interested in the happenings in Dragonstone, but Melisandre’s insistence that his daughter, Shireen, stay involved suggests something good could be brewing. With Lysa gone, Selyse is all we have left for wild-eyed women living in remote castles. Forget burning people at the stake— we’re ready to see her bring some fire to Westeros in general. That is, if Dany’s dragons don’t get there first.

After a few more tightly focused episodes, “Mockingbird” jumped all over the map tonight; as Joanna has already pointed out, many of the storylines seemed to be part of the same conversation about siblings, underlining the ongoing Lannister drama as well as a possibly imminent reunion between Sansa and Arya. With only three episodes left, the season is building toward a series of different major conflicts, which means it’s always a surprise when something like Lysa’s death, or Joffrey’s, gets tossed into a buildup episode.

As we saw tonight when Arya only now learned of Joffrey’s death, it takes a while for even a major assassination to trickle down to the rest of Westeros. But I’m looking forward to Lysa’s death causing some chaotic ripples for the rest of the characters—while biting my nails awaiting Oberyn’s showdown with The Mountain. Some characters you’re thrilled to see fly out the Moon Door, but the Viper I’ll be clinging to as long as possible.